Compression
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Tourer
Joined: Jul 2007
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Compression
Hello, haven't been on the forum for years now, before this was the place I'd go for help. I been riding gone thru a few thousand mile on my last ride, and now have 52,000 miles on my current ride Street glide 2011 96ci.
No major upgrades but the usual exhaust, intake, and Power vision from Fuel Moto. Gonna open the cam chest to check on my tensioners and replace them, but then also would like to install SE204 cams for little more power. Today I decided to check my compression just to be sure its where it's supposed to be. First I checked my compression cold and my readings were 180 front, 180 rear, then I checked it warm and it was 190 front, 175 rear. I added a little oil to the rear cylinder and tried again warm and my readings were 190 on both.
I didn't ride the bike before the test I just let it idle for a few minutes to warm up the engine.. Could my warm readings be that uneven cause I didn't ride the bike to operating temperature? Why would my cold readings be even?...could it be my rear cylinder rings are worn out and by adding oil my readings evened out?
My bike still runs strong, no hesitation, no smoking, just wanted to replace the tensioners and add a cam in the process.
No major upgrades but the usual exhaust, intake, and Power vision from Fuel Moto. Gonna open the cam chest to check on my tensioners and replace them, but then also would like to install SE204 cams for little more power. Today I decided to check my compression just to be sure its where it's supposed to be. First I checked my compression cold and my readings were 180 front, 180 rear, then I checked it warm and it was 190 front, 175 rear. I added a little oil to the rear cylinder and tried again warm and my readings were 190 on both.
I didn't ride the bike before the test I just let it idle for a few minutes to warm up the engine.. Could my warm readings be that uneven cause I didn't ride the bike to operating temperature? Why would my cold readings be even?...could it be my rear cylinder rings are worn out and by adding oil my readings evened out?
My bike still runs strong, no hesitation, no smoking, just wanted to replace the tensioners and add a cam in the process.
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,156
Likes: 11,244
From: San Diego, CA
I can't find my old 96" manual, but I believe the minimum spec was at least 125psi, and less than 10% difference between cylinders...
Whether you go with 180/180psi test or the 190/175psi test..... you would be within spec and nothing to worry about.....
If you want, test it again and see what it reads... then if you still suspect an issue, do a leak down test....
Good luck with the mods
Whether you go with 180/180psi test or the 190/175psi test..... you would be within spec and nothing to worry about.....
If you want, test it again and see what it reads... then if you still suspect an issue, do a leak down test....
Good luck with the mods
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